Fluid-tight package



Oct, 22,1946. H. F. WATERS FLUI-D-TIGHT PACKAGE Original Filed April 27; 1940 c M WL P J0 2 m 2 MH o s y www 2 ,f E 2 N m 5 ,i 5 w 2 s u INVENTOR. HH//ryA-WATERS BY /wvlwlp Q.

ATTORNEY Patented Get. 22, 1946 dans FLUID-TIGHT PACKAGE Harry F. Waters, New York, N. Y.

Original application April 27, 1940, Serial No.

331,907. Divided and this application December 4, 1941,

Serial No. 421,583

4 Claims. (Cl. 229-55) The present invention relates to fluid-tight packages formed of composite sheet materials, and more particularly to such packages having inner cushioning surfaces.

This application is a division of my application Ser. No. 331,907, led April 27, 1940, for Punctureproof composite sheets and method of making the same.

.Heretofore various composite sheets were proposed for the purpose of fluid-tight packages. Generally speaking, these prior sheets included a base of non-fusible character and a thermo-plastic and fusible coating or layer on said base which determined the fluid-tight character of the iinished product and made it possible to unite and to seal a sheet of this type with sheets of similar type by the application of heat and pressure. While these prior sheets were satisfactory in operation for fluid-tightly packaging liquids and certain other commodities which had to be sealed and preserved against the eiiect of atmospheric influences, difficulties were experienced particularly in packaging granular materials such as, for example, coffee. As those skilled in the art know, it is desirable to pack fresh roasted and ground coffee in a vacuous atmosphere or in an atmosphere devoid of aid and substantially constituted of carbon-dioxide. When coffee was packed in a eXible-walled, fluid-tight container and the air was removed from such container, the external pressure had the effect of strongly pressing the container walls against the sharp granules of the contents. Especially when the packed coffee was of the steel-cut variety, extremely sharp edges were present on the individual granules and these edges tended to cut through the paper' when this was pressed against the granules by the external atmospheric pressure. As a result, frequently leakage points or areas developed and made the value of this type of vacuum-packing problematical. Although it was already suggested to provide liner materials of accentuated thickness and strength which were capable of resisting cutting eects of sharp granules, such liner materials were relatively expensive and increased the cost of the packaging method. Likewise, as far ,as I am awa-re, none of the various other suggestions and proposals made in the past was completely `satisfactory and Successful on a practical and commercial scale.

It is a feature of novelty of the present invention to provide huid-tight packages having a cushioning layer generally not `fusible or lluidtight in character constructed Iand arranged to reinforce the liner in the region `where it is exposed to the mechanical effects of the contents,

regions where a heat-seal but leaving intact the Y provided.

fusible material is to be Other and further objects and advantages ofV the invention will become apparent from the following descrption taken in conjunction with the accompanying drawing, in which:

Fig. 1 illustrates a plan view of a composite sheet in the form of a strip or web for forming fluid-tight packages and having a flexible cushioning layer or member attached to pre-determined regions thereof;

Fig. 2 is a section taken on line 2 2 of Fig. Vl;

Fig. 3 depicts the strip or web Shown in Fig. `1 after it has been folded about its longitudinal medial line;

Fig. 4 is a section taken on line 4 4 of Fig. 3

Fig. 5 illustrates a plan View of a portion of the strip shown in Fig. 3 after it has beenl separated into unit lengths and has been heat-sealed at two edges thereof to form an envelope; l

Fig. 6 shows a perspective view of an envelope formed from the structure of.Fig. 5 with its lateral marginal portions bent up;

Fig. 7 is a perspective view of the envelope shown in Figs. 5 and 6 in its squared-up position and having its bottom formed and sealed;

Fig. 8 is a section taken on line V8 3 of Fig. 7

Fig. 9 is a section taken on line 9--9 of Fig. '7, the thickness of the materials being greatly eriaggeratedfor reasons of clarity; and

Fig. 10 is a perspective view of a nished iluidtight package formed from the envelope shown in Figs. 1 tor 9.

Figs. 1 to 8 illustrate an embodiment of my invention in which the fluid-tight and punctureproof character of a package is obtained by the provision of `a cushioning layer provided on top of the composite sheet. This cushioning layer or member does Vnot have to be of a fluid-tight or fusible character, its only object being to provide mechanical reinforcement of the sheet and of the finished package against puncturing influences. The structure and the operation of this modified sheet will be best understood in connection with the description of the procedure of forming a.f

fluid-tight package therefrom.

The general structure and arrangement 0f this sheet will be readily understood from Figs. land 2, showing a .composite sheet in fthe form of `a strip vor web for the continuous production of Huid-tight packages. This sheet orV stripfcomprises a base l20 constituted of paper or 0f some similar exible land sheet-like material. This base is provided with a thermo-plastic and fusible covering layer 2 |,generally covering the complete form the seams of .the

surface of the base. This suitable covering layer may be provided by means of a coating method or by means of a calendering method of the type disclosed in my co-pendlng application, Serial No. 329,254, led on April 12, 1940, now Patent No. 2,228,647, of January 14, 1941. On top of covering layer 2| I provide individual rectangular elements 22 of a suitable cushioning material secured to the fusible covering layer 2| by lines 23 of a suitable adhesive preferably of the type which remains flexible after drying, such Aas latex. Cushioning members 22 have only the object of reinforcing the inner surface of this composite sheet or liner against mechanical influences and they do not have to contribute to the fluid-tightness of the finished .package which is provided by liner 2|. Likewise, it is not necessary to have cushioning layers 22 of a thermo-plastic or fusible character but it is sufcient to provide such restri-cted dimensions thereof .that they will leave at least the major por-tion` of the heat-sealing regions of the nished sheet or strip uncovered so that such uncovered fusible regions may be united by the application of heat and pressure. In the instant case the dimensions of cushioning members 22 are such as to permit heat-sealing of the strip in the regions around the same, denoted by reference character 24, which subsequently will finished package, as it will appear hereinafter. Although various flexible materials may be used for the cushioning members 22, I prefer .to employ a thin but very strong and tough paper having a very dense and puncture-resisting structure su-ch as glassine paper.

In forming a package from the finished strip, the first step is to fold the Strip along its longitudinal .center line 25. This, same as all of the other subsequent operations, may be accomplished manually, but, in actual practice generally, automatic machinery will be employed, such as a forming plate in connection with conventional auxiliary devices. Figs. 3 and 4 show the strip after it has been folded along center line 25. The strip may be heat-sealed along spaced transverse lines forming transverse seams 26 which divide the space between the folded-over portions of the strip into container spaces. Here- `after, the strip may be cut along lines 21 whereby individual fluid-tight envelopes are obtained.

The appearance of one of these` envelopes is 5. It will be readily observed in shown in Fig. this figure that the finished envelope iscompletely at, is sealed by seams 26 at two edges thereof and has its top-edge 28 Vopen for the introduction of materials to be packedtherein. Attention is directed to the circumstance that Vcushioning member 22 will form an inner layer or envelope within the outer envelope and due to the presence of glue lines 23 this cushioning member or envelope will open and close `together with the outer envelope. Of course, instead of the provision of these glue lines bonding only certain portions of the cushioning membe-r to the envelope, the complete surface of the Vcushioning member may be bonded to the envelope by means of a similar adhesive. It will be noted that the side edges and the top edges of cushioning member 22 do not extend into the seams 26 so that in this region only the corresponding portions of thermo-,plastic layer 2l are placed into a face to face contact.l Of course, there is no objection to having the side edges of the ycushioning member extending into a portion of the'heatseam in order to have them firmly bondedwith and locked in the seam, After the envelope with 4 the innermost cushioning and protective layer has been completed, its lateral marginal portions 29 may be folded back, this having the object of placing seams 26 beyond fold lines 3i) and thereby to provide additional protection for the seam. In addition, it will be observed that due to the dimensions of cushioning member 22, its side edges 3| will likewise be beyond fold lines 39 so that these edges are also protected and are placed into a region which is not accessible to contact with the contents packed within the inner space of the finished envelope, -or container. The envelope may now loe squared-up (Fig. 7) and its bottom portion may be folded in. This squaring-up operation may be accomplished by means of a suitable device such as a mandrel, may be accomplished manually or may be carried out by previously attaching the finished envelope to an outer .carton formed separately or simultaneously with rthe formation of the envelope as this is disclosed, for example, in my co-pending application, Serial No. 329,254, filed on yApril 12, 1940,v

now Patent No. 2,228,647. It will be readily seen in Fig. 7 that cushioning member 22 will provide a complete inner bag or container within thehI-lnished squared-up envelope so that after the iinished container is filled with contents, such as coffee, the granules of the contents will be at n place in direct contact with the thermo-plastl layer or film 2 I, Thus, a very strong protection will be obtained against puncturing influences and generally speaking, the danger of puncturingV by sharp grains of the packed material will be eliminated.

The exact structure of the interlocking por-- tions of the outer envelope and of the inner cushioning layer or bag will be best understood from Fig. 9 which is a section taken on line 9-9 of Fig. 7, the dimensions of the thermo-plasticcoated or covered paper sheet 32 and of the cushioning layer or sheet being greatly exagger--I ated for reasons of clarity. Likewise, to increase the clarity of illustration, the paper base and the thermo-plastic layer on the inner face thereof have been illustrated as a single layer 32, rather than two layers 20 and 2|, as in Figs. 1 to 4. Fig. 9 clearly shows that the lateral ends of outer envelope 32 are fluid-tightly sealed by means of a seam 26 and that n 34 thus formed lis turned down flat along the end Walls of the squared-up envelope, or container. The side edges 3| of cushioning member or bag 22 are placed face tov face against each other and are carried beyond medial fold line 30 and extend into the base portion of nn 34. They are retained in this position by friction which in itself assures sufficient stability of the structure. As a modification, it is also possible to further extend the side edges 3| of the cushioning member to partially protrude into seam 26 whereby a more rigid interlocking of envelope and cushioning member is obtained. This interlocking effect may be further accentuated by coating or printing at least the' laterali terminal regions of cushioning member 22 withathin layer ofV a thermo-plastic material which is fused during the provision of seam'26 and pro` vides a strong and permanent bond between envelope and cushioning member.

After filling the internally lined or cushionedv container, the air is preferably withdrawn therefrom and the mouth portions of the container are hermetically sealed by means of a completely flat top seal provided by the application of heat and pressure. The upper marginal portions of; the container may be :folded down in the formasco,sesr

C9 oftabs S35. similar' :to the corresponding tabs of the bottom portions" ofY` theV container- Preferably, theldimensionsof'cushioning member 22 are sodetermined as to4 have it extend sufficiently upwards toward the-Irnouth opening of the container to 'prevent' direct `Contact between the granules of the packed material and the inner walls 32 ofthe package. In fact, in some'cases -itis advantageous toextend the upper edges of the cushioning member or bag until the region where the top transverse seam is provided whereby the packed material will: be completely and positively surrounded by the cushioning memberi.v i

\ The external appearancel of the finished package 33 is illustrated in Fig. 1). While this package. hasM been shown Aas of a completely rectangular structure, it` will be obvious to those skilled in the art that after removal of the internal atmosphere from the package, the walls thereof will collapse around the contents, and, as a result, the shape of the package will be distorted to a smaller or greater extent.

Of course, it will be readily appreciated that a wide variety of thermo-plastic materials may be employed for forming the self-sustaining films and coatings incorporated into the composite sheets of the invention. Preferred thermo-plastic materials are, for example, certain types of rubber compounds, particularly rubber hydrochloride products sold under the name of Koroseal and Pliolm, certain vinyl resins such as particularly a vinyl derivative sold under the name Vinylite V, which is a co-polymerized vinyl chloride and vinyl acetate. Of course, various other thermo-plastic and re-fusible materials may be used and at present a large number of such materials is available on the market, as those skilled in the art know. It is essential that the thermoplastic and re-fusible material should be capable of providing flexible, tough, non-tacky, moistureproof and gas-proof films of a self-sustaining character.

Likewise, the laminating agent employed in connection with the embodiments of the invention shown in Figs. 3 and 4 of my parent application, above-identied may be of various character in accordance with the thermo-plastic material to be laminated. Generally, the laminating agent should contain a thermo-plastic material similar to the one of which the thermo-plastic layer to be laminated is constituted, a suitable solvent therefor, and a plasticizing agent, for `example a plasticizing agent sold under the name of Santicizer l5, 16 or 17, and comprising respectively ethyl phthalyl ethyl glycollate; butyl phthalyl butyl glycollate; and methyl phthalyl ethyl glycollate. As a practical example, a laminating agent constituted of about 60 parts by weight of acetone, about 20% by weight of a suitable vinyl resin, and about 20% by weight of Santicizer 17 provides good results for laminating a selfsustaining thermo-plastic sheet constituted of a similar vinyl resin. This laminating agent is a viscous liquid which may be readily spread on or applied to the surfaces to be laminated.

It is essential that the selfsustaining thermoplastic material forming the top layer of the composite sheet should originally contain a smaller amount of the same plasticizer than the laminating agent so that after the lamination, the plasticizer present in the laminating agent in a higher relative amount should migrate into the top layer where such plasticizer is present in a lower relative amount. I have found that when it was attempted to'directly incorporate such accentuated amounts of plasticizer into the top film such lm became tacky and difficult to use and 4to laminate, while when such high percentage of plasticizer was gradually obtained by the' slow migration of the plasticizer from the laminatingagent intoY the top layer, such tackinesswas avoided and a desirable yielding and stretchabla veryslowly agi-ngflmwas obtained.4 The'probable reason for this` curious' phenomenonis that the migratory plasticizer, 'while permeating most of the thickness of the top layer, will not bepresent in the upermost surface or skin portion thereof which tliuswilli act as Va non-tacky protective layer. Of course, my inventionk is independent from the correct or incorrect nature of this theoretical conside-ration. Y'

In some cases whenV the top layer to be laminated is constituted of a polyvinyl alcohol or of regenerated cellulose, it is possible to use an aqueous solution of glycerine and gelatine as a laminating agent, the glycerine being the migratory plasticizer proper while the gelatine acts as a type of inhibitor t0 prevent unduly rapid migration of the plasticizer.

The paper employed as a base may be any suitable paper according to the type of application contemplated, for example kraft paper. The ilexible cushioning member or layer may be a strong and dense paper of reduced thickness, such as glassine paper. As a rule, the cushioning member or layer is not relied upon for maintaining the fluid-tight character of the package and, consequently, does not haveto be of a fluid-tight material for the cushioning member or to provide a cushioning member which is fusible on at least one face thereof.

It is to be observed that the composite sheets of the invention maybe employed for the production of fluid-tight packages in a manner similar to prior liner materials but at the same time are capable of eliminating the danger of leakage due to pin holes, punctures and similar mechanical defects.

Moreover, the invention contemplates a novel type of composite strip having individual. cushioning members incorporated therein which may be of any extremely inexpensive character but, nevertheless, may have a very great mechanical strength Without interfering with the heatscalable character of the finished package.

Although the present invention has been described in connection with a few preferred embodiments thereof, variations and modifications may be resorted to by those skilled in the art without departing from the principles of the present invention. Thus, while the cushioning member has been illustrated as formed simultaneously with the formation of the package or envelope proper, it may be also provided in the form of a pre-fabricated bag or envelope which is subsequently inserted into the fluid-tight and heatscalable envelope. I consider all of these variations and modifications as Within the true spirit and scope of the present invention as'disclosed in the foregoing description and dened by the appended claims.4

I claim: Y

l. A composite strip for the continuous production of puncture-proof fluid-tight packages which comprises in combination a strip of flexible material fusible on at least one face thereof, and a plurality of `puncture-resistant exible cushioning members spacedly secured to the fusible face of said strip, said strip being adapted to be'sep- 7 arated into unit lengths for theformation of individual packages, each of said unit lengths includingl at leastvone cushioning member arranged in suchposition as to cover'the portions Which in the finished package Will be in direct contact with the packed material and t0 leave uncovered the portions which are to be heat-sealed during forming and after the lling of said package.

`2. In paper containers having inner thermoplastic surfacings formed integral with the paper and interfusedvto form hermetic Wall and closure seams, the improvements comprising cushioning glassine liners adhered to said thermoplastic surfacingsand covering the entire inner surface of the containers when in iinished, sealed-01T condition. I

3. In paper containers having inner thermoplasticsurfacings formed integral with the paper and interfus'ed to form hermetic Wall and closure seams, the improvements comprising cushioning glassine liners adhered to said thermoplastic surfacings adjacent the mouths only ofV the s containers, and covering the. inner surfaces thereof when the said containers are in finished, sealedoii condition. v

4. A paper container comprising a Wrapping which is hermetically sealed, said container being formed of a composite paper sheet having an inner thermoplastic liquid-proof surfacing and a separate cushioning glassine layer adhered to the liquid-proof surfacing, the Whole being folded into a closed shell and sealed closed by the interfusion of juxtaposed sections of the inner thermoplastic surfacing. i

HARRY F. WATERS- 

